What Do Emotional Disorders Have In Common? How Brain Structure Plays A Role

Psychological disorders may present themselves in different ways, but they can be more intertwined than you'd think. Certain disorders, like depression and anxiety, often go hand in hand, and scientists have spent years investigating what causes emotional disorders have in common. Recently, a paper published in the journal NeuroImage: Clinical may shed light on the latter. When researchers from the University of Illinois in Chicago compared the brain structures of patients with different mental illnesses, they found something surprising: Many share similar disruptions in their white matter, or the tissue connecting different parts of the brain.

According to Science Daily, a group of researchers led by Dr. Scott Langenecker analyzed data from 37 studies looking at the brain structures of people with major depression, obsessive compulsive disorder (OCD), bipolar disorder, social anxiety disorder, or post-traumatic stress disorder (PTSD). Perhaps unsurprisingly, each disorder was associated with abnormal brain function compared to the control participants, but one difference was found across the board: A disruption in the white matter structure connecting parts of the brain known as the "default mode network." This area is associated with passive thinking — the thoughts you have when you're not focused on a task, like daydreaming or idle memories. Basically, it's in charge of your mind's background static rather than conscious, directed thoughts.

According to researchers, disruptions in connectivity between these parts of the brain make sense. Many emotional disorders are characterized by repetitive negative thoughts, and if the white matter connecting the default mode network functions poorly, it could go a long way toward explaining why these thoughts persist. Surprisingly, patients with OCD showed the most similarities to other emotional disorders. Although it's not uncommon for people to have OCD along with another type of disorder, the symptoms of OCD are famously distinct, or so researchers thought. According to Science Daily, co-author Dr. Olusola Ajilore said that these findings indicate the disorder "clearly has more in common with other emotional disorders than we think."

In contrast, patients with PTSD had the least in common with other participants, showing low white matter connectivity in areas that functioned well in people with other disorders. Bipolar disorder also stood out; while most of affected areas in other disorders were found in the left side of the brain, people with bipolar disorder showed disruptions on both sides.

Of course, there's no way to tell whether white matter disruptions cause the disorders or vice versa. However, the paper adds to a growing body of research showing how closely brain structure and psychological disorders are intertwined — maybe bring that up next time someone says mental illness is all in someone's head.